NEW YORK - The bull market slowed to a trot but didn't stop this winter. Stocks have been buffeted since the start of the year by plunging oil prices, a surging dollar and worries about the timing of a potential rate increase by the Federal Reserve.

NEW YORK (Reuters) - U.S. stocks ended near their session lows on Tuesday, in a retreat from the previous session's sharp rally, but the S&P 500 and the Nasdaq Composite posted their ninth consecutive quarter of gains.

IRS Commissioner John Koskinen, who runs the 87,000 employee tax agency, had a candid response to that sentiment Tuesday. "Politics are politics," he said after a speech at the National Press Club in Washington.